Construction of random decapeptide library and screening identification of angiogenin-binding peptides

A random decapeptide library was constructed by using phage-surface display. The oligonucleotide sequence (NNK) was digested with Sfi I and Not I and ligated into the phagemid pCANTAB5E. The recombinant DNA was introduced into E. coli TG1 by electroporation, and 5.3X10~(7) phage was harvested. The insert was present in 66.7% of phage, thus the random decapeptide library had a complexity of 3.53X10~(7). The titer of phage supernatant was 4.8X10~(11) after the helper phage M13KO7 super-infection. This library was screened using angiogenin protein. 26 ANG-binding clones were indentified from 94 enriched individual phagemid clones after two rounds of panning, the nucleotide sequences encoding peptide recombined in 12 positive phagemid clones were determined. ELISA showed that all of them could specifically bind to ANG.